1. Field of the Invention
The present invention relates to a semiconductor optical modulator and a method for manufacturing a semiconductor optical modulator.
2. Description of the Related Art
Japanese Unexamined Patent Application Publication No. 2004-53830 discloses a Mach-Zehnder optical modulator disposed on a semiconductor substrate. The Mach-Zehnder optical modulator according to Japanese Unexamined Patent Application Publication No. 2004-53830 includes a phase modulation electrode disposed on an optical waveguide and a slot-line electrode disposed apart from the optical waveguide. The phase modulation electrode and the slot-line electrode are connected together with an air-bridge wiring. The air-bridge wiring has a hollow space therebelow.